[Bug 1821441] Re: Clocksource changes from TSC to HPET after sleep. Kills performance.
[Expired for linux-signed-hwe (Ubuntu) because there has been no activity for 60 days.] ** Changed in: linux-signed-hwe (Ubuntu) Status: Incomplete => Expired -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821441 Title: Clocksource changes from TSC to HPET after sleep. Kills performance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1821441/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1821441] Re: Clocksource changes from TSC to HPET after sleep. Kills performance.
Has the problem been observed in kernel versions 5.x? Like in Ubuntu 20.04 onward? ** Changed in: linux-signed-hwe (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821441 Title: Clocksource changes from TSC to HPET after sleep. Kills performance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1821441/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1821441] Re: Clocksource changes from TSC to HPET after sleep. Kills performance.
I'm seeing the same thing. Basically, any use of clock_gettime now requires a syscall (isntead of using vsdo). The applications I'm running do a lot of clock_gettime's, and basically cannot run performantly anymore after this happens. This machine is a: System Information Manufacturer: Alienware Product Name: Alienware Aurora Ryzen Edition Version: 1.0.1 cpu: processor : 31 vendor_id : AuthenticAMD cpu family : 23 model : 113 model name : AMD Ryzen 9 3950X 16-Core Processor stepping: 0 microcode : 0x8701013 kernel: 4.15.0-121-generic #123-Ubuntu SMP Mon Oct 5 16:16:40 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux kernel log after resuming from sleep: Oct 14 15:28:59 viable kernel: [ 3442.068452] Measured 70 cycles TSC warp between CPUs, turning off TSC clock. Oct 14 15:28:59 viable kernel: [ 3442.068455] tsc: Marking TSC unstable due to check_tsc_sync_source failed Oct 14 15:28:59 viable kernel: [ 3442.068472] TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'. Oct 14 15:28:59 viable kernel: [ 3442.068473] sched_clock: Marking unstable (3442081459163, -14096408)<-(3442040805073, 27665648) Oct 14 15:28:59 viable kernel: [ 3442.068582] cache: parent cpu1 should not be sleeping Oct 14 15:28:59 viable kernel: [ 3442.068845] CPU1 is up Oct 14 15:28:59 viable kernel: [ 3442.067786] clocksource: Switched to clocksource hpet -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821441 Title: Clocksource changes from TSC to HPET after sleep. Kills performance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1821441/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1821441] Re: Clocksource changes from TSC to HPET after sleep. Kills performance.
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: linux-signed-hwe (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821441 Title: Clocksource changes from TSC to HPET after sleep. Kills performance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1821441/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1821441] Re: Clocksource changes from TSC to HPET after sleep. Kills performance.
** Summary changed: - Clocksource changes from TRC to HPET after sleep. Kills performance. + Clocksource changes from TSC to HPET after sleep. Kills performance. ** Description changed: This has been verified with a freshly reset bios. Every time I sleep - Ubuntu and wake, the clock gets switched from TRC to HPET - and then + Ubuntu and wake, the clock gets switched from TSC to HPET - and then processes such as gnome-shell take up an excessive amount of CPU (with trace showing clock_gettime being the culprit) - and general performance is severely degraded. Here is the relevant part of syslog: Mar 23 08:18:19 JTR4 kernel: [ 2921.476536] TSC synchronization [CPU#0 -> CPU#4]: Mar 23 08:18:19 JTR4 kernel: [ 2921.476537] Measured 532 cycles TSC warp between CPUs, turning off TSC clock. Mar 23 08:18:19 JTR4 kernel: [ 2921.476538] tsc: Marking TSC unstable due to check_tsc_sync_source failed Mar 23 08:18:19 JTR4 kernel: [ 2921.476545] TSC found unstable after boot, most likely due to broken BIOS. Use 'tsc=unstable'. Mar 23 08:18:19 JTR4 kernel: [ 2921.476546] sched_clock: Marking unstable (2920879403495, 582702087)<-(2921692577659, -216036333) Mar 23 08:18:19 JTR4 kernel: [ 2921.476773] cache: parent cpu4 should not be sleeping Mar 23 08:18:19 JTR4 kernel: [ 2921.476839] microcode: CPU4: patch_level=0x0800820b Mar 23 08:18:19 JTR4 kernel: [ 2921.477161] CPU4 is up Mar 23 08:18:19 JTR4 kernel: [ 2921.477177] clocksource: Switched to clocksource hpet This is in 18.04 LTS HWE, with an Asus Zenith Extreme Alpha motherboard and AMD Threadripper 2990WX CPU. This looks like it is linked to this bug - as someone in the comments here shows a trace with clock_gettime using up excessive CPU, as well: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1773959 ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.18.0-16-generic 4.18.0-16.17~18.04.1 ProcVersionSignature: Ubuntu 4.18.0-16.17~18.04.1-generic 4.18.20 Uname: Linux 4.18.0-16-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.9-0ubuntu7.5 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Sat Mar 23 08:47:06 2019 InstallationDate: Installed on 2019-03-12 (11 days ago) InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210) SourcePackage: linux-signed-hwe UpgradeStatus: No upgrade log present (probably fresh install) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821441 Title: Clocksource changes from TSC to HPET after sleep. Kills performance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe/+bug/1821441/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
